K-spar configuration for bonded wing construction

ABSTRACT

A method and apparatus of bonded wing construction in which skins ( 35, 39 ) having shaped protrusions ( 37, 41 ) are bonded to rib members having correspondingly shaped intrusions ( 33 ). The skins may also include differently shaped protrusions ( 53, 55 ) which are bonded to K-shaped spars ( 51 ) having correspondingly shaped intrusions ( 61, 63 ).

This application claims the benefit of provisional application No.60/194,610 filed Apr. 5, 2000.

TECHNICAL FIELD

The present invention relates to aircraft wing construction. Inparticular, the present invention relates to a method and apparatus fora bonded wing construction.

DESCRIPTION OF THE PRIOR ART

Traditionally, aircraft wing structures were constructed by fasteningC-shaped channel spars to the ends of ribs and by mechanically fasteningI-beam-stiffened skins to angle clips disposed in channels in the wingribs. These systems rely purely on mechanical assembly for spar to skinand skin to rib interfaces.

SUMMARY OF THE INVENTION

There is a need for a bonded wing construction which does not relypurely upon mechanical assembly to establish the necessary spar to skinand rib to skin interfaces without compromising the stiffness of thewing.

Therefore, it is an object of the present invention to provide a methodand apparatus for bonded wing construction that does not rely purelyupon mechanical assembly to effectuate the skin to rib interface and thespar to rib interface, and which does not sacrifice wing stiffness.

The above objects are achieved by providing a method and apparatus ofbonded wing construction in which skins having generally rhombus shapedprotrusions are bonded to rib members having correspondingly shapedintrusions. The skins may also include triangular shaped protrusionswhich are bonded to K-shaped spars having correspondingly shapedintrusions.

The present invention has significant advantages, including: (1) onlyabout 5% mechanical assembly; (2) less complex assembly; (3) a reductionin part counts, detail fabrication, assembly fastener installation, andassociated assembly recurring costs; (4) a reduction in the complexityof assembly tool design and non-recurring tool procurement costs; and(5) reduction in skin manufacturing costs and cycle time.

The above objects and advantages, as well as others, will be evidentfrom the following detailed description of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an assembly view of a prior-art wing structure.

FIGS. 2A and 2B are assembly views of the K-spar bonded structureconfiguration of the present invention.

FIG. 3 illustrates the bond socket concept of the present invention.

FIG. 4 is an enlarged view of the bond socket concept of FIG. 3 for aforward spar.

FIG. 5 is an enlarged view of the bond socket concept of FIG. 3 for anaft spar.

FIG. 6 is an assembly view of the K-spar bonded structure configurationof the present invention used in a torque box application.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1 in the drawings, a prior-art wing construction isillustrated. A rib 11 includes channels 13 into which are mechanicallyinstalled angle clips 15. Angle clips 15 are mechanically coupled toI-beams 17 carried by an upper stiffened skin 19 and a lower stiffenedskin 21. A C-shaped spar 23 is coupled to rib 11 and/or upper and lowerskins 19 and 21. This is a typical mechanical assembly which requires arelatively large number of parts and which requires a complex assemblyprocess.

Referring now to FIGS. 2A and 2B in the drawings, the K-spar bondedstructure configuration of the present invention is illustrated. A rib31 includes a plurality of generally rhombus shaped intrusions 33. Anupper stiffened skin 35 includes a plurality (only one shown) ofgenerally correspondingly rhombus shaped protrusions 37 that are alignedwith rib intrusions 33 on the upper surface of rib 31. In a similarfashion, a lower stiffened skin 39 includes a plurality (only one shown)of generally correspondingly rhombus shaped protrusions 41 that arealigned with rib intrusions 33 on the lower surface of rib 31. It shouldbe understood that the geometric shape of the protrusions can varywidely from application to application.

A K-shaped spar, or K-spar, 51 is configured to conform to the end ofrib 31. As best seen in FIG. 2B, K-spar 51 is also wedge shaped in thevertical direction, having a protruding ridge 57 which mates with anintruding channel 59 in one or more ribs 31. Upper skin 35 includes atriangular protrusion 53. Likewise, lower skin 39 includes a triangularshaped protrusion 55. K-spar 51 includes an upper triangular intrusion61 and a lower triangular intrusion 63. It should be understood thatupper and lower triangular intrusions 61 and 63 may be of other shapes.

Skin 35 includes a tab portion 65, and skin 39 includes a tab portion67. K-spar 51 includes corresponding upper and lower tab portions 69 and71.

When assembled and bonded together using conventional techniques andbonding materials, protrusions 37 on upper skin 35 and protrusions 41 onlower skin 39 interlockingly mate with intrusions 33 in rib 31;protrusions 53 on upper skin 35 and protrusions 55 on lower skin 39interlockingly mate with upper intrusions 61 and lower intrusions 63,respectively on K-spar 51; and tab portions 65 and 67 mate with tabportions 69 and 71, respectively. Also, protruding ridges 57interlockingly mate with channels 61. This configuration provides largesurface areas for which to bond these component parts together andcreate a stiff structure. This can be done with only about 5% mechanicalassembly, as opposed to the 100% mechanical assembly associated with theprior art.

Referring now to FIG. 3 in the drawings, the assembled and bondedstructure is illustrated. The bonding pattern is shown in bold.

Referring now to FIG. 4 in the drawings, an enlarged view of a forwardK-spar and the bond socket concept according to the present invention isillustrated. The bonding pattern is shown in bold.

Referring now to FIG. 5 in the drawings, an enlarged view of a forwardK-spar and the bond socket concept according to the present invention isillustrated. The bonding pattern is shown in bold.

It should be understood that the method of the present invention can beused to configure a wide variety of structures, not just aircraft wings.

Referring now to FIG. 6 in. the drawings, the present invention isillustrated in a torque box application.

The present invention has significant advantages, including: (1) onlyabout 5% mechanical assembly; (2) less complex assembly; (3) a reductionin part counts, detail fabrication, assembly fastener installation, andassociated assembly recurring costs; (4) a reduction in the complexityof assembly tool design and non-recurring tool procurement costs; and(5) reduction in skin manufacturing costs and cycle time.

Although the present invention is shown in a limited number of forms, itis not limited to just these forms, but is amenable to various changesand, modifications without departing from the spirit thereof.

What is claimed is:
 1. A structure for an aircraft, comprising: a ribspar having first and second opposed surfaces, and at least one endsurface connecting the first and second opposed surfaces, wherein thefirst and second opposed surfaces each have at least one intrusiontherein; a K-spar bonded to the rib spar end surface, the K-spar havingfirst and second intrusions respectively adjacent the first and secondrib spar opposed surfaces; a first skin member bonded to the first ribspar surface, wherein the first skin member has a first protrusion nearan end thereof adapted to fit into the K-spar first intrusion, and atleast one additional protrusion adapted to fit into the rib spar firstsurface intrusion; and a second skin member bonded to the second ribspar surface, wherein the second skin member has a first protrusion nearan end thereof adapted to fit into the K-spar second intrusion, and atleast one additional protrusion adapted to fit into the rib spar secondsurface intrusion.
 2. The structure of claim 1, further comprising: atleast one end intrusion in the rib spar end surface; and correspondingat least one protrusion on the K-spar, wherein the K-spar protrusion isadapted to fit into the rib spar end surface intrusion.
 3. The structureof claim 2, wherein the rib spar end surface intrusion has a triangularcross-section, and the K-spar protrusion has a matching triangularcross-section.
 4. The structure of claim 1, wherein the K-spar first andsecond intrusions each have a triangular cross-section, and wherein thefirst and second skin member first protrusions each have a triangularcross-section that matches the K-spar first and second intrusions,respectively.
 5. The structure of claim 1, wherein the rib spar firstand second opposed surface intrusions have a rhombus-shapedcross-section, and the first and second skin member protrusions eachhave a rhombus-shaped cross-section that matches the rib spar first andsecond opposed surface intrusions.
 6. The structure of claim 1, whereinthe rib spar has a second end surface opposite the end surface, andfurther comprising: a second K-spar bonded to the rib spar second endsurface, the second K-spar having first and second intrusionsrespectively adjacent the first and second rib spar opposed surfaces;wherein the first and second skin members additionally have secondprotrusions near respective second ends thereof, such second intrusionsadapted to fit into the second K-spar first and second intrusions,respectively.
 7. The structure of claim 1, wherein the K-spar includesat least one protrusion extending away from the rib spar end surface,and approximately coplanar with the rib spar first surface, and whereinthe first skin member includes a projecting portion at the end that isbonded to the K-spar protrusion.
 8. A method for assembling a structurefor an aircraft, comprising the steps of: providing a rib spar havingfirst and second opposing surfaces and at least one end surface, thefirst and second opposing surfaces each having at least one intrusiontherein; bonding a K-spar to the rib spar end surface, wherein theK-spar has first and second intrusions therein adjacent the rib sparfirst and second surfaces; and bonding first and second skin members tothe first and second rib spar surfaces, respectively, wherein the firstand second skin members each have protrusions corresponding to, andadapted to mate with, the rib spar surface intrusions and the K-sparfirst and second intrusions, respectively. 9.The method of claim 8,wherein the bonding steps comprise bonding the spars and memberstogether with a bonding material.